Signaling system



SIGNALING SYSTEM Filed Jan. 24, 1928 Figl Inventor:

Hu h EAHen His Attorney Patented Mar. 3, 1931 STATES HTSEZ il- HUGH E. ALLEN, F S COTIA, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY,

' A CORPORATION OF NEW YORK SIGNALING SYSTEM 7 Application filed January 24, 1928. Serial No. 249,181.

My invention relates to signaling systems and more particularly to receiving circuits employed in connection with such systems. These circuits as commonly constructed employ electron discharge devices which are utilized for the purpose of convertingthe received high frequency impulses into direct current or into unidirectional impulses of low frequency which may be used to operate necthe like. 7

The purpose of my invention is to provide a receiving system. of the type indicated in which the electron discharge devices employed are energized by alternating current of. commercial frequency and which is more reliable in its operation and more sensitive to high frequency currents of comparatively small magnitude than systems which have been used in the past.

In Patent No. 1,626,480 to L. J. Perkins, April 26, 1927, is'shown a receiving device in which an electron discharge device of the usual glow tubeconstruction is controlled in accordance with the current in the anode circuit of a three elementdevice having a heated cathode, the anode and grid of which are supplied with alternating potential, and which is in turn controlled by the received signal currents. I have found that greater quantities of energy may be released and hence'mor-e reliable operation of signal ape paratus may be had by utilizing a plurality of electron discharge devices having heated cathodes and in which the anodes, and preferably the control electrodes, are energized with alternating currents and by controlling subsequent devices in the circuit by current impulses of the 7 power supply frequency which are produced by device s prior in" the circuit in response to received signal impulses. I

vThe novel features which I believe to be characteristic of my invention will be set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects or ad: vantages thereof may best be understood by reference to the following description taken essary receiving apparatus, such as relays and in connection with the accompanying drawing in which Fig. 1 represents one embodiment of my invention and Fig. 2 a modification thereof.

Referring to Fig. 1 of the accompanying drawing 1 and 2 represent electron discharge devices which are employed in my receiving circuit. 3 represents a transformer having a primary winding which is connected with a source of alternating current 4 of commercial frequency and a plurality of secondary windings 5, 6 and 7 for energizing the grid, cathode and anode circuits respectively of the electron discharge devices 1, 2. The anode circuit of the device 1 is supplied with potential from winding 7 through a circuit which includes the primary winding of a transformer 8, a portion of the winding 7 and the cathode circuit of the device 1. Similarly the anode of the device 2 is supplied with potential through a circuit including the signal device 9 which is represented in the form of a relay, winding 7, and the cathode circuit of the device 2. The grid of the dischargedevice 1 is supplied with potential through a circuit which includes the secondary winding of a transformer 10, re sistance 11, a portion of the winding 5 and the cathode circuit of the device 1; and the grid of the device 2 is supplied with potential through a circuit which includes'the resistance 12, winding 5 and cathode circuit of the device 2. The transformer connections are so made that the grid and anode of each device are connected to potential points opposite each other with respect to the cathode or;ncutral connection and thus are'energized in opposite phase relation. The secondary winding of the transformer 8 is connected between the grid of the electron discharge former 10 may be tuned by means of a condenser 14 to the frequency of the signal currents, although if desired this may be dispensed with and the distributed capacity of the transformer may be relied upon for the nece sai'y tuning of the grid circuit of the device 1.

As thus arranged the operation of my device is as follows. lVlien no signal currents are impressed upon the primary windingof the transformer 10 comparatively little or no current will flow in the anode circuit of either of the discharge devices, due to the fact that the potentials which are impressed upon the grids thereof from the winding 5 are of opposite phase relation with the potentials which are impressed upon the anodes by the winding '7 and are of suilicient magnitude substantially to prevent the how of current in the anode circuits. hen, however, signal currents are impressed upon the transformer ll) a potential having the frequency of the signal currents will appear upon the grid of the discharge device 1. This potential will cause an increase in the average current flowing in the anode circuit during the half cycles of the power supply currents when the anode is at positive potential. Thus a pulsating potential having the frequency of the power supply currents will appear across the secondary w nding of the transformer 8. This winding is so connected to the grid and so poled that this potential opposes the potential nermally 'applied to the grid of the device 2 by the winding 5 with the result that when the anode of the device 2 is positive the grid of this device will. become diminishingly ncgativeor even positive depending upon the intensity of the signal currents with the result theta substantial flow of current will be caused in the anode circuit of this device, thereby causing the operation of the relay 9 which may, by means of its contacts 10 and in control any desired apparatus.

The arrangement shown in Fig. 2 (litters from that shown in Fig. 1 only in that the grid bias voltage for the device 2 is supplied in series with the secondary winding of the transformer 8 rather than in shunt therewith as is done in Fig. l. The desirability of this modification is dependent largely upon the nature of the transformer 8. If, for example, the secondar; 1 winding of this transfo'rn ier is of high inductance it may occur that due to energy stored therein the grid of the device 2 will remain to some extent positive after the anode of the device has become positive. When this occurs a short rush of current will flow in the anode circuit at the beginning of each operative half cycle of the device 2. To prevent operation of the relay 9 in response to this current it is necessary that it should be adjusted in a niai'ii'i'e'r which weuid "make it less sensitive than would otherwise be the case. This disadvantage may be overcome by utilizing the shunt connection shown in Fig. 1. The mentioned rush of current will also occur in the device 1 due to energy stored in the transformer 10 when the grid of the de vice 1 is positive. This rush of current from the anode of device 1 will cause additional energy to be stored in the transformer 8 thereby producing a cumulative effect upon the grid of device 2. This flow of current at the beginning of the operative half cycle of the devices may further be reduced, or eliminated, by connecting resistances 11 and 12 in the grid circuit of each of these devices, these resistances having a magnitude such that substai'itially no grid current flows during the half cycle of the power supply currents when the grid is positive. Hence substantially no energy may be stored in the windi ugs of the transformers l0 and 8 and the 1.80 degree phase relation between the grid and plate voltage of the two devices will not be impaired.

While I have shown and described mv iiivention in connection with three element electron discharge devices in each of which the grid is biased negatively when the anode is positive thereby causing the devices to operate as biased detectors or electron discharge relays, it will of course be understood that I do not wish to be limited thereto since it is apparent that the grid bias upon either or both of the devices may be had by using the well-known grid leak and condenser combination. Furthermore, either or both of these devices may be of two element rather than three element construction.

Vhile I have shown and described specific embodiments ofiny invention it will of course be i'uiderstoml that I do not wish to be limited tl i'ere'to, since many modifications, both in the circuit arrangement and in the instrumentaliti'es employed may be made without departing from the spirit and scope of my invention.

VVha-t I claim as new and desire to secure by Letters Patent of the United States, is

1 In a high frequency signal system, a pair of three electrode discharge devices, each of said devices having grid and anode circuits, means for supplying alternating potential to the grid and anode circuits of each device in opposite phase relation, means for supplying signal current 'to the grid circuit of one of said devices, means operable respon'sively to the anode current in the other device, and coupling means so connected and poled between said devices that when anode current news in said first device a pulsating potential is supplied to the grid of said other,

device having the frequency of the potential normally supplied thereto.

2. In a high frequency signal system, a pair of three electrode electron discharge devices, each" of said devices having grid and and poled that when current flows in said.

anode circuit a pulsating potential is sup plied to the grid of said other device having the frequency of, and which is opposed to, the potential normally supplied thereto.

3. In a high frequency signal system, a pair of electron discharge devices, each of said devices having an anode, a cathode and a grid, a source of alternating current, connections from a neutral point on said source to said cathodes and from opposite points on said source to the grid and anode of each device such that the potential supplied to the grid and anode of each device are in opposite phase relation, means for supplying signal current to the grid of one of said devices, means responsive to the current flowing in the anode of the other device, coupling means connected between the anode of said first device and the grid of said second device and means for tuning said coupling means to the frequency of said source.

4:. In a signal receiving system, an electron discharge device having an anode, a cathode and a grid, a source of alternating potential, connections fro-m a neutral point on said source to said cathode and from opposite points on said source to said grid and anode such that said grid and anode are energized in substantially opposite phase relation, an electron discharge relay which is controlled by received signal currents, and coupling means responsive to said relay for supplying to the grid of said device a pul-.

sating potential having the frequency of said source and of a polarity Which is opposed to the negative half cycles of the potential normally applied to said grid, and means opera said discharge device.

5. In a high frequency signal system, a plurality of electron discharge devices, each of said devices having an anode circuit, a cathode circuit and a grid circuit, means for energizing the anode circuits of said devices with alternating current, meansfor supplying signal current to the grid of one of said devices, current responsive means connected in the anode circuit of another of said devices and a coupling means connected between the anode circuit of said first device and the grid circuit of said second device whereby pulsating current having the frequency of said energizing current and of such polarity able responsively to the anode current in thatit opposes the negative halfcyclo of the potential normally supplied to the grid of said second device is supplied 'to said grid to affect the anode; current flowing in lsaid device.- v

6. In a high frequency signal-systennkt plurality of electron discharge devices,'- each of said devices having a heatedcathode and an. anode, means for energizing sa d anodes .with alternating currents, means for supplying signal ,currents to one of said devices to affect the current flowing in the anode circuit thereof, means operable responsively to the current in the anode circuit'of another of said devices, andcouplingmeansconnecting said devices whereby when high frequency currentsare supplied to said first'device a pulsating potential having the frequency of said ener izing currents and of opposed polarity to thatof the potential normally supplied to the other device, is supplied to said other device to cause operation of said anode current responsive means. I

7. In combinatioma pair of electron discharge devices, each of said devices having an anode, a cathode and a grid, a source of alternating current, connectlons from a neutral point on said source to said cathode and from opposite points on said source to the grid and anode of each device, the potential" supplied to said grids of said devices being such that substantially no anode current normally flows therein, a. transformer connection between the anode circuit of one of said devices and the grid circuit of the other of said devices,means for supplying signal cur rents to the grid of said first device, means responsive to the anode current of said other device and means for reducing the grid current in both of said devices substantially to zero.

8. In a high frequency signal system, a pair of electron discharge devices, each of said devices having an anode circuit, means for supplying alternating currents to said anode circuits in like phase relation, means for supplying signal currents to one of said devices to control the anode current therein, means responsive to the anode current ofthe other device, coupling means connected bc-- tween said devices, and means for tunin said coupling means to the frequency of the alternating currents normally supplied to said anode circuits. 1

9. The method of operating an electron discharge device in a high frequency system electron discharge de'ice having an anode, 

